The present invention relates to a lighted knob provided with a lighted indicator which illuminates a character, symbol, or numeral at night and, more particularly to a lighted knob which illuminates to facilitate the discrimination of whether or not a nameplate for indicating control items has been properly mounted in a specific position.
Various types of equipment are provided with knobs for performing on-off operation and predetermined control operation of the equipment. As these knobs, lighted knobs have been in wide use for the ease of identification of their control purpose or on-off condition by illuminating a nameplate on the knobs in order to ensure correct knob manipulation even in the gloom and at night.
A lighted switch knob for opening and closing a slide roof of an automobile will be explained as one example of the lighted knob by referring to FIGS. 4 and 5.
FIG. 4 is a plan view showing the switch knob with the nameplate removed, and FIG. 5 is a vertical cross section, partly cut off, of the switch knob.
A lighted knob 1 to be operated to open and close a slide roof is fitted, on a body 5, with three nameplates: a control item nameplate 2 placed at the center thereof to indicate the operation of the slide roof; a first operation nameplate 3 placed beside the control item nameplate 2, for closing the roof; and a second operation nameplate 4 for opening the roof. The control item nameplate 2 has a code "ROOF" in relief indicating a control item; the first operation nameplate 3 is formed to indicate the contour of a car in relief; and the second operation nameplate 4 is formed to indicate the contour of a car in relief with the roof opened. The knob body 5 is produced from a synthetic resin and provided with three light transmission holes 6, 7 and 8 drilled in the front part and covered with the three nameplates 2, 3 and 4. On the peripheral edge of each of the light transmission holes 6, 7 and 8 is formed a step section 9 lowered at least by the thickness of the nameplates 2, 3 and 4. The peripheral edge section of the nameplates 2, 3 and 4 is bonded to the step section 9 with an adhesive. Each of the nameplates 2, 3 and 4, the details of which constitution is not illustrated, is composed of a nameplate sheet on which a transparent character, contour, etc. for example are printed, and a transparent, heat-resisting protective sheet affixed on the back side through an adhesive layer. Also, when a colored character or contour is used, filling a clear colored ink between the nameplate sheet and an adhesive layer is sufficient. Behind the knob body 5 are arranged light sources 11, 12 and 13 for illuminating the nameplates 2, 3 and 4 respectively. A projecting wall 14 provided on the back side of the knob body 5 serves to shield the light from an adjacent light source.
Since most nameplates have a symmetrical shape such as rectangular and square as illustrated, incorrect assembling is very likely to occur by securing the nameplates 2, 3 and 4 upside down to the light transmission holes 6, 7 and 8 respectively at the time of lighted knob assembling. Furthermore, in the above-described lighted knob 1, the first and second operation nameplates 3 and 4 are of the same size and therefore there will also occur an error in assembling the knob in which the second operation nameplate 4 is secured to the light hole 7 for the first operation nameplate 3.
In order to prevent such an incorrect assembling, there are adopted nameplate sheets of different shapes, and the knob body is provided with a receiving section which conforms to these shapes, and also is provided with a recess. At the same time the nameplate is provided with a projection, which fits in the recess. However, if various many types of nameplate sheets are prepared, many kinds of dies also will be needed correspondingly, resulting in an increased cost and complicated parts control.